Naslov
Analysis of neutron flux around medical electron linear accelerator placed in the room reconstructed after decommissioning of 60Co units using monte carlo simulation

Autori
Brkić, Hrvoje ; Ivkovic, Ana ; Poje Sovilj, Marina ; Kasabašić, Mladen ; Jurković, Slaven ; Faj, Dario

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Physica Medica / Paolo Russo - Atena : Elsevier, 2016, 306-306

Skup
1st European Congress of Medical Physics

Mjesto i datum
Atena, Grčka, 01.09.2016. - 04.09.2016

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Monte Carlo ; 60Co ; Vault

Sažetak
Introduction Increased neutron flux around high energy medical electron linear accelerators placed in the rooms reconstructed after decommissioning of 60Co unit has been reported before. Purpose The main limitation of the reported room was the space. Extremely short maze was used and walls were strengthened by lead. In this study, Monte Carlo simulation is used to analyze the reasons for increased neutron flux. Materials and methods A model of 18 MV photon beam linear accelerator with the room was built using the MCNP611 code. Points at several locations and different accelerator orientations were used to evaluate the neutron and photon ambient dose equivalent to which medical personnel could be exposed. Also, the different maze lengths was used in simulation to evaluate its significance for neutron protection. Then neutron sources, spectra, flux and dose equivalent were analyzed. Results Calculated neutron dose equivalent was not negligible from the aspect of personal dosimetry with almost 2 mSv/year per person in area occupied by staff (conservative estimation). The wall enhancement by lead was new source of photoneutrons. Simulated longer mazes significantly decreased neutron flux near the room door. Both, the lead enhancements and different lengths of mazes changed neutron spectra significantly in chosen points. Conclusion The study confirms that shielding from neutron radiation should be thoroughly analyzed if high energy linear accelerators are put in the room where the space constraints exist. The lead enhancement of walls and short mazes should be avoided. If this is not possible, lower energy photon beams should be used.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA